The invention relates to self cooling containers, and in particular to sorption self cooling containers. Previous inventions relating to sorption self cooling and self heating containers have been described by the present author in U.S. Pat. Nos. 4,250,720, 4,736,599, and 4,928,495, by Thomas et al in U.S. Pat. No. 4,759,191, and by Sabin et al in U.S. Pat. No. 4,901,535. Essentially, the self cooling containers consists of a chamber containing water, the boiling point of which has been lowered by an air vacuum in the chamber. The chamber communicates reversibly with another chamber containing a desiccant which removes the vapor generated by the low boiling point water. By closing the communication between the water-refrigerant and desiccant chambers the self cooling device can be stored indefinitely without losing its cooling potential. The cooling action is initiated by opening of the communication between the refrigerant and the desiccant chambers. In all of the above inventions the refrigerant and the beverage to be cooled are placed in separate containers. As the refrigerant boils it cools itself to its relatively low boiling point temperature. The refrigerant then cools the surfaces of its container. The cold surfaces of the container then cool the beverage which is placed outside of the refrigerant container. Thus, the cooling of the beverage is dependent upon heat transfer from the beverage to the refrigerant through the surfaces of the cold container. This requires the construction of relatively large heat conducting surfaces between the refrigerant and the beverage. This transfer of heat takes more time than the cooling of the refrigerant which occurs almost instantaneously during the boiling of the refrigerant. The main objective of the present invention is to obtain a direct and instantaneous cooling not only of the refrigerant but also of the beverage. This is achieved by adaptations which mix the beverage and the refrigerant in the same chamber, and allow a direct communication between the beverage-refrigerant mixture and the desiccant chamber. The refrigerant consists of water, the boiling point of which has been lowered by an air vaccum. The beverage used consists of any non-carbonated drink such as juice or ice tea as will be described.
Because of the direct communication between the beverage and the desiccant additional means are required to prevent a contamination of the beverage by the desiccant. This is achieved by a semi-permeable barrier between the chambers which prevents the passage of desiccant particles and allows the free passage of water vapor. In addition, a water absorber is placed in the desiccant chamber to prevent a contamination of the beverage by liquid which has entered or formed in the desiccant chamber. A more detailed description of the novel feature of the invention is given in the Detailed Description section.